Use substitution to find the indefinite integral.

${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{x^3-3x}{x^4-6x^{2}7}dx$

${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{x^3-3x}{x^4-6x^{2}7}dx=$

$$

$($Use parentheses to clearly denote the argument of each functi